Hollow structure magnetic field driven vacuum variable capacitor and radio frequency source matching device

Abstract

The application relates to the field of electronic technology and discloses a hollow-structure magnetic-field-driven vacuum variable capacitor and radio frequency source matching device, which comprises a base, the top end of the base is connected with an insulating shell, the top end of the insulating shell is provided with a metal shell, and a hollow insulating tube is arranged between the base and the metal shell. In the application, the built-in driving coil in the hollow insulating tube is electrified, the coil generates a magnetic field force under the action of the current, the magnetic field force is coupled to a permanent magnet fixed on the inner moving electrode of the vacuum capacitor, the movable electrode moves perpendicularly to the current direction of the coil, the relative area between the movable electrode and the fixed electrode is changed, the capacitor capacity is changed, compared with the existing variable vacuum capacitor, breakthroughs are made in performance, structure, function and the like, the vacuum capacitor has the characteristics of high speed, high response, high matching precision, increased service life, long-term stable vacuum degree sealing performance and small size.

Description

Technical Field

[0001] This invention belongs to the field of electronic technology, and in particular relates to a hollow structure magnetic field driven vacuum variable capacitor and an RF source matching unit with the hollow structure magnetic field driven vacuum variable capacitor. Background Technology

[0002] In the current electronics field, vacuum capacitors are widely used in high-power radio frequency oscillation circuits and impedance matching, as well as in plasma plating, etching and plasma cleaning processes in the semiconductor industry. Because the capacitance value is adjustable and they operate in a high-frequency, high-power electromagnetic field environment, they have high process requirements. Therefore, variable vacuum capacitors are generally expensive and are key semiconductor equipment components. The market and technology are monopolized by Japanese and Swiss manufacturers.

[0003] An adjustable vacuum capacitor consists of a stator disk, a moving disk, electrode rings, a ceramic tube, a rotating screw, a guide sleeve, a positioning nut, a conductor bellows, a sleeve, a metal shell, and a fixed rod. Existing variable vacuum capacitors adjust their capacitance by applying a bridge circuit to both sides of the shell insulator. The adjusting screw drives the movable electrode, causing the bellows to compress or stretch, thus changing the relative area between the movable and fixed electrodes. The current capacitance value is displayed by the changes in the bridge circuit values ​​on the testing instrument. The conductor bellows serves as the current path for the moving electrode and also allows the moving electrode to move while simultaneously sealing the vacuum.

[0004] Currently available adjustable vacuum capacitors have the following drawbacks during use:

[0005] 1. Wear of rotating screw: Due to the change of capacitor value, the screw needs to be rotated frequently, which causes severe wear of the rotating screw and positioning nut. This increases the screw clearance, makes the capacitor value adjustment inaccurate, and easily leads to thread stripping and damage.

[0006] 2. Bellows elastic fatigue: When the bellows is in operation, it continuously reciprocates, which can easily lead to bellows elastic fatigue, causing cracks on the surface of the bellows, which can damage the vacuum environment, reduce insulation performance, and make it easy for arcing to occur between capacitor electrodes, resulting in damage.

[0007] 3. Excessive adjustment time: In semiconductor manufacturing, production time must be strictly controlled, especially in advanced processes below 14nm, which require millisecond-level adjustment and matching speed. When adjusting the capacitance value, the traditional vacuum variable capacitor screw mechanical rotation adjustment method is slow and the matching time is too long, resulting in low semiconductor chip production efficiency and yield, which can no longer meet application requirements. Summary of the Invention

[0008] (a) Technical problems to be solved

[0009] To address the shortcomings of existing technologies, this invention provides a hollow structure magnetic field-driven vacuum variable capacitor and an RF source matcher, eliminating the use of rotating screws and bellows. It achieves breakthroughs in performance, structure, and function, and enables the hollow variable capacitor to have the characteristics of high speed, high response, high matching accuracy, increased service life, long-term stable vacuum sealing, and small size, thus solving the problems raised in the background technology.

[0010] (II) Technical Solution

[0011] To achieve the above objectives, the present invention provides the following technical solution: a hollow structure magnetic field driven vacuum variable capacitor, including a base, an insulating shell connected to the top of the base, and a metal shell installed on the top of the insulating shell, and a hollow insulating tube disposed between the base and the metal shell;

[0012] A fixed electrode is connected to the top of the base, and a movable electrode is provided above the fixed electrode. A moving electrode current connection piece is connected to the top of the movable electrode.

[0013] The innermost ring of the movable electrode is a permanent magnet, and a shielding layer is provided between the movable electrode and the permanent magnet.

[0014] The movable electrode is driven by a drive coil above the fixed electrode.

[0015] Preferably, the two ends of the hollow insulating tube are fixed to the base and the metal shell respectively, and the central axis of the hollow insulating tube coincides with the central axis of the metal shell. The hollow insulating tube is installed through the movable electrode, and a driving coil is installed inside the hollow insulating tube. An electric field shielding material layer is installed on the inner wall of the hollow insulating tube.

[0016] Preferably, the hollow insulating tube is fixedly installed at the central axis of the base and the metal shell, and the upper base, the insulating shell and the metal shell form a vacuum chamber outside the fixed electrode and the movable electrode.

[0017] Preferably, the operating range of the fixed electrode and the movable electrode is the vacuum chamber composed of the base, the insulating shell and the metal shell. The bottom end of the fixed electrode is fixedly connected to the base, and the central axis of the base coincides with the central axis of the hollow insulating tube.

[0018] Preferably, the outer wall of the moving electrode current connection piece is in close contact with the inner wall of the vacuum chamber composed of the upper base, the insulating shell, and the metal shell.

[0019] Preferably, the bottom end of the moving electrode current connecting piece is fixedly installed to the top end of the movable electrode, and multiple sets of moving electrode current connecting pieces are arranged equidistantly around the axis of the hollow insulating tube.

[0020] Preferably, the movable electrode forms a lifting structure with the fixed electrode via a drive coil, a permanent magnet, and the movable electrode is evenly distributed at equal intervals above the fixed electrode.

[0021] Preferably, a drive coil is wound around the outer wall of the insulating shell.

[0022] An RF source matching device includes an RF source matching device with a hollow structure magnetic field-driven vacuum variable capacitor.

[0023] (III) Beneficial Effects

[0024] Compared with the prior art, the present invention has the following beneficial effects:

[0025] 1. In this invention, by energizing the drive coil inside the hollow insulating tube, the coil generates a magnetic field under the action of the current, which couples to a permanent magnet fixed on the moving electrode inside the vacuum capacitor. This causes the moving electrode to move perpendicular to the direction of the coil current, thereby changing the relative area between the moving electrode and the fixed electrode, and thus changing the capacitance. Compared with existing variable vacuum capacitors, this invention represents a breakthrough in performance, structure, and function, giving the vacuum capacitor the characteristics of high speed, high response, high matching accuracy, increased service life, long-term stable vacuum sealing, and small size. In addition, the drive coil can output different forces at the same position, and can also output a constant force at any position. Compared with the original variable vacuum capacitor structure, this design allows for faster (50-500ms) capacitance adjustment, higher accuracy, and more convenient control.

[0026] In this invention, by embedding a driving coil inside a hollow insulating tube and using electric field shielding material on the inner wall of the permanent magnet, the magnetic fields of the permanent magnet and driving coil are prevented from inducing the electrodes at high frequencies, and the mutual magnetic field interaction is greatly reduced. Furthermore, the hollow structure inside the hollow insulating tube is rationally utilized and optimized, increasing the structural utilization rate of the vacuum capacitor and further improving the matching accuracy. At the same time, due to the built-in driving coil, the volume is further reduced, allowing it to be applied to more precise small-volume instruments. This enables the vacuum capacitor to meet the needs of different products, further realizing the innovation and development of vacuum capacitors, thereby promoting the production efficiency and product yield of the semiconductor chip industry, and has broad development prospects. Attached Figure Description

[0027] Figure 1 This is a front cross-sectional view of the hollow magnetic field driven vacuum variable capacitor in this invention.

[0028] Figure 2 This is a three-dimensional cross-sectional schematic diagram of the hollow magnetic field driven vacuum variable capacitor in this invention;

[0029] Figure 3 This is a schematic diagram of the connection structure between the shielding layer and the permanent magnet in this invention;

[0030] Figure 4 This is a schematic diagram of the exploded structure of the hollow magnetic field driven vacuum variable capacitor in this invention;

[0031] Figure 5 This is a schematic diagram of the external structure of the hollow magnetic field-driven vacuum variable capacitor in this invention.

[0032] Figure 6 This is a front cross-sectional view of an existing vacuum capacitor with adjustable capacitance.

[0033] Figure 7 A schematic diagram of the connection structure of an existing vacuum capacitor with adjustable capacitance.

[0034] Figure 8 A schematic diagram of the open structure of an existing vacuum capacitor with adjustable capacitance.

[0035] Figure 9 This is a schematic diagram of the external structure of an existing vacuum capacitor with variable capacitance.

[0036] Figure 10 This is a cross-sectional structural diagram of Embodiment 3 of the present invention;

[0037] Figure 11 This is a structural topology diagram of the RF source matching unit in Specific Embodiment 1;

[0038] Figure 12 for Figure 11 The diagram shows the structural topology of the matching module for the hollow magnetic field-driven vacuum variable capacitor in this specific embodiment.

[0039] In the diagram: 1. Base; 2. Insulating shell; 3. Metal shell; 4. Hollow insulating tube; 5. Moving electrode current connection piece; 6. Movable electrode; 7. Fixed electrode; 8. Drive coil; 9. Shielding layer; 10. Permanent magnet. Detailed Implementation

[0040] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0041] Please see Figures 6-9Existing vacuum capacitors with adjustable capacitance consist of a stator disk, a mover disk, an electrode ring, a ceramic tube, a rotating screw, a guide sleeve, a positioning nut, a conductor bellows, a sleeve, a metal shell, and a fixed rod. A bridge circuit is applied to both sides of the shell insulator to test and adjust the capacitance value. The adjusting screw drives the movable electrode, causing the bellows to compress or stretch, thus changing the relative area between the movable and fixed electrodes. The current capacitance value is displayed by the changes in the bridge circuit values ​​on the testing instrument. The conductor bellows serves as the current path for the movable electrode and also allows the movable electrode to move while simultaneously sealing the vacuum.

[0042] Example 1

[0043] Please see Figures 1-5 A hollow structure magnetic field driven vacuum variable capacitor includes a base 1, an insulating shell 2, a metal shell 3, a hollow insulating tube 4, a moving electrode current connection piece 5, a movable electrode 6, a fixed electrode 7, a drive coil 8, a shielding layer 9, and a permanent magnet 10. The top of the base 1 is connected to the insulating shell 2, and the top of the insulating shell 2 is equipped with the metal shell 3. A hollow insulating tube 4 is set between the base 1 and the metal shell 3. According to the Lorentz principle, the magnitude of the current flowing through the drive coil 8 determines the movement distance of the moving electrode.

[0044] A fixed electrode 7 is connected to the top of the base 1, and a movable electrode 6 is provided above the fixed electrode 7. A movable electrode current connecting piece 5 is connected to the top of the movable electrode 6. The number of blades of the movable electrode current connecting piece 5 can be modified according to the magnitude of the current flowing through the guide rod. The function of the movable electrode current connecting piece 5 is to connect the movable electrode 6 to the outer shell and measure the capacitance value.

[0045] The innermost ring of the movable electrode 6 is a permanent magnet 10, and a shielding layer 9 is provided between the movable electrode 6 and the permanent magnet 10. The shielding layer 9 is divided into an electric field material shielding layer 9 and a magnetic field material shielding layer 9, which isolates and shields the mutual electromagnetic induction between the electric field and magnetic field generated by the electrode and the permanent magnet 10 and the drive coil 8 during operation, thus avoiding adverse effects.

[0046] Please see Figures 1-2 The two ends of the hollow insulating tube 4 are fixed to the base 1 and the metal shell 3 respectively, and the central axis of the hollow insulating tube 4 coincides with the central axis of the metal shell 3. The hollow insulating tube 4 is installed through the movable electrode 6. The hollow insulating tube 4 is equipped with a driving coil 8 inside, and the inner wall of the hollow insulating tube 4 is equipped with an electric field shielding material layer. By utilizing the hollow interior of the hollow insulating tube 4, the matching accuracy is further improved. Furthermore, due to the built-in driving coil 8, the volume is further reduced, and it can be applied to more precise small-volume instruments.

[0047] Please see Figures 1-5The hollow insulating tube 4 is fixedly installed at the central axis of the base 1 and the metal shell 3. The upper base 1, the insulating shell 2 and the metal shell 3 form a vacuum chamber outside the fixed electrode 7 and the movable electrode 6. By energizing the drive coil 8 inside the hollow insulating tube 4, the drive coil 8 generates a magnetic field under the action of the current, which is coupled to the permanent magnet 10 fixed on the movable electrode 6 inside the vacuum capacitor, so that the movable electrode 6 moves perpendicular to the current direction of the drive coil 8, thereby changing the relative area between the movable electrode 6 and the fixed electrode 7, and thus changing the capacitance.

[0048] Please see Figures 1-2 The operating range of the fixed electrode 7 and the movable electrode 6 is the vacuum chamber composed of the base 1, the insulating shell 2 and the metal shell 3. The bottom end of the fixed electrode 7 is fixedly connected to the base 1, and the central axis of the base 1 coincides with the central axis of the hollow insulating tube 4. The fixed electrode 7 and the shell are connected together. The inner ring of the movable electrode 6 is a permanent magnet 10, and the hollow insulating tube 4 penetrates the movable electrode 6.

[0049] Please see Figures 1-4 The outer wall of the moving electrode current connecting piece 5 is in close contact with the inner wall of the vacuum chamber composed of the upper base 1, the insulating shell 2, and the metal shell 3. The inner wall of the hollow insulating tube 4 is provided with an electric field shielding material layer. According to the theory that the electric field inside the shielding cavity is zero, the driving coil 8 inside the hollow insulating tube 4 is affected by the high-frequency electromagnetic field of the capacitor electrode. At the same time, it also avoids the magnetic field of the permanent magnet 10 and the driving coil 8 from inducing the high-frequency electrode, and greatly reduces the mutual magnetic field interaction.

[0050] Please see Figures 1-4 The bottom end of the moving electrode current connecting piece 5 is fixedly installed with the top end of the movable electrode 6, and the moving electrode current connecting piece 5 is arranged in three sets at equal intervals around the axis of the hollow insulating tube 4. By rationally utilizing the hollow structure inside the hollow insulating tube 4 by incorporating the drive coil 8, the structure has been optimized, increasing the structural utilization rate of the vacuum capacitor.

[0051] Please see Figures 1-3 The movable electrode 6 forms a lifting structure with the drive coil 8, the permanent magnet 10 and the fixed electrode 7. The movable electrode 6 is evenly distributed above the fixed electrode 7. At the same position, the drive coil 8 can output different forces. At any position, the drive coil 8 can also output a constant force.

[0052] like Figure 11-12As shown, an RF source matching device includes an RF source matching device with a hollow structure magnetic field-driven vacuum variable capacitor; the RF source matching device is used for impedance matching of the plasma cavity to facilitate the RF source to output maximum power and reduce the reflection loss of the input signal. As a key component of plasma in the semiconductor field, the RF source matching device is used to match the impedance of the load cavity in order to maximize the transmission of RF source power.

[0053] RF source: AE Paramount; HFi matcher: AE Navigator

[0054] Working principle: When a voltage is supplied to the drive coil 8 from the outside, the drive coil 8 generates a driving force magnetic field under the action of the current. At the same time, the internal permanent magnet 10 generates an induced electromotive force with a constant magnitude and direction. Because the current of the drive coil 8 is different, and because the induced electromotive force generated by the permanent magnet 10 is different, under the interaction of the two magnetic fields, the movable electrode 6 moves perpendicular to the current direction of the drive coil 8. The moving electrode current connecting piece 5 connects to the movable electrode 6 to move. The change in the relative area between the two electrodes changes the capacitance of the vacuum capacitor.

[0055] The magnetic field generated by the permanent magnet 10 has the same polarity as the magnetic field generated by the driving coil 8. The energized driving coil 8 will generate a force in the magnetic field. If the magnetic fields of the permanent magnet 10 and the driving coil 8 are consistent, the magnitude of the force is proportional to the current of the driving coil 8, F = BIL, where L is related to the shape and length of the driving coil 8, and B is the magnetic field. The larger the current, the greater the force. The magnetic flux generated by the permanent magnet 10 is Ψ = B·Scosθ, where θ is the angle between B and S. The magnetic field is constant, the area S = Πr2 is constant, and θ is 0. Therefore, the magnetic flux of the permanent magnet 10 is constant.

[0056] When the drive coil 8 is energized, the motional electromotive force generated by the drive coil 8 is E = BLV, where L is related to the shape and length of the drive coil 8, B is the magnetic field that remains constant, and V is the velocity. The motional electromotive force generated by the drive coil 8 is proportional to L and V. The induced electromotive force generated by the permanent magnet 10 is the same in magnitude and direction as the motional electromotive force generated by the drive coil 8. That is, the direction of motion of the movable electrode 6 is only related to the current and length of the drive coil 8.

[0057] The direction of motion of the movable electrode 6 changes the height h between the two capacitor polarities, thereby changing the capacitance C. The higher the height h between the two polarities, the larger the capacitance C. The capacitance C is directly proportional to the height h.

[0058] Example 2

[0059] To compare the parameter differences between this embodiment and existing vacuum capacitors with variable capacitance, the existing capacitor model SCV-510M is compared with the hollow structure magnetic field-driven vacuum variable capacitor in this embodiment:

[0060] The external dimensions of the SCV-510M vacuum capacitor are set as 140 mm in length × 73 mm in diameter, and the weight is W = 1.3 kg. The polarity height h of the two capacitors is 0-35 mm. The shaft can rotate a total of 12 times. With one rotation of the shaft, the moving electrode moves 3 mm. 35 mm - 1000 picofarads, or 1 mm - 28.6 picofarads. 12 rotations - 1000 picofarads, or 1 rotation - 83.4 picofarads. That is, with one rotation, the moving electrode moves 3 mm, and the capacitance changes by 82.94 picofarads.

[0061] In this embodiment, the external dimensions of the variable vacuum capacitor are 130mm in length × 73mm in diameter, and the mass m = 1.2 kg. When the force generated by the driving coil 8 and the force generated by the permanent magnet 10 are equal in magnitude and opposite in direction, and the time t = 1 second, the length of the driving coil 8 is L = 1 meter, the capacitor mass m = 1.2 kg, the capacitor diameter d = 73 mm, the Ampere force F = BIL, the electromotive force E = BLV = ΔΦ / dt, the velocity V = ΔΦ / FLI, V = h / t, the polarity height of the two capacitors h = ΔΦ / FLtI, that is, the larger the current I, the higher the polarity height h of the two capacitors, and the larger the capacitance C. That is, the current I = 1 mA, the polarity height h of the two capacitors is 1 mm, and the capacitance C = 28.6 picofarads.

[0062] The vacuum capacitor is tested using the following steps:

[0063] Step 1: Use a bridge circuit to test the capacitance value;

[0064] Step 2: Use a withstand voltage tester to apply a high AC voltage across the two ends of the variable vacuum capacitor to confirm whether the variable vacuum capacitor is normal within the test voltage range.

[0065] Based on the above data, it can be concluded that the variable vacuum capacitor of this invention has external dimensions of 130mm in length and 73mm in diameter, and a mass of m = 1.2 kg. Compared with existing vacuum capacitors, it has a smaller volume while keeping other parameters unchanged. When adjusting the capacitance, it offers faster adjustment speed and higher accuracy. Furthermore, the vacuum capacitor of this invention has improved its structure, optimizing issues such as losses and slow matching speed in the original design. This results in a vacuum capacitor with high response, high speed, small size, easy control, and high matching accuracy, greatly optimizing structural and matching speed shortcomings. This allows the vacuum capacitor to meet the needs of different products, further realizing the innovation and development of vacuum capacitors, thereby promoting the production efficiency and product yield of the semiconductor chip industry, and possessing broad development prospects.

[0066] Example 3

[0067] Please see Figure 10 The difference between this embodiment and embodiment 1 is that the outer wall of the insulating shell 2 of the hollow structure magnetic field driven vacuum variable capacitor is wound with a driving coil 8;

[0068] The patent publication number for this embodiment is CN215955107U;

[0069] The disadvantage of this embodiment compared to embodiment 1 is that embodiment 1, due to its built-in drive coil, has a further reduced size and can be applied to more precise small-volume instruments, enabling vacuum capacitors to meet the needs of different products, further realizing the innovation and development of vacuum capacitors, thereby promoting the production efficiency and product yield of the semiconductor chip industry, and has broad development prospects.

[0070] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A hollow-structure magnetic-field-driven vacuum variable capacitor comprising a base (1), characterized in that: The top end of the base (1) is connected with an insulating shell (2), and the top end of the insulating shell (2) is installed with a metal shell (3), and a hollow insulating tube (4) is arranged between the base (1) and the metal shell (3); The top end of the base (1) is connected with a fixed electrode (7), and an upper portion of the fixed electrode (7) is provided with a movable electrode (6), and the top portion of the movable electrode (6) is connected with a movable electrode current connecting sheet (5); The innermost circle of the movable electrode (6) is a permanent magnet (10), and a shielding layer (9) is arranged between the movable electrode (6) and the permanent magnet (10); The movable electrode (6) is driven by a driving coil (8) above the fixed electrode (7); Both ends of the hollow insulating tube (4) are fixed with the base (1) and the metal shell (3), respectively, and the central axis of the hollow insulating tube (4) coincides with the central axis of the metal shell (3), and the hollow insulating tube (4) is arranged through the inside of the movable electrode (6), the inside of the hollow insulating tube (4) is provided with the driving coil (8), and the inner wall of the hollow insulating tube (4) is provided with an electric field shielding material layer; The hollow insulating tube (4) is fixedly installed at the central axis of the base (1) and the metal shell (3), and the upper base (1), the insulating shell (2) and the metal shell (3) form a vacuum chamber outside the fixed electrode (7) and the movable electrode (6); The actuation range of the fixed electrode (7) and the movable electrode (6) is the vacuum chamber composed of the base (1), the insulating shell (2) and the metal shell (3), the bottom end of the fixed electrode (7) is fixedly connected with the base (1), and the central axis of the base (1) coincides with the central axis of the hollow insulating tube (4); The movable electrode (6) forms a lifting structure between the driving coil (8), the permanent magnet (10) and the fixed electrode (7), and the movable electrode (6) is uniformly distributed at equal intervals above the fixed electrode (7).

2. The hollow structure magnetic field driven vacuum variable capacitor according to claim 1, characterized in that: The outer side wall of the movable electrode current connecting sheet (5) is connected with the inner wall of the vacuum chamber composed of the upper base (1), the insulating shell (2) and the metal shell (3).

3. The hollow structure magnetic field driven vacuum variable capacitor according to claim 1, characterized in that: The bottom end of the movable electrode current connecting sheet (5) is fixedly installed with the top end of the movable electrode (6), and the movable electrode current connecting sheet (5) is arranged with multiple groups about the axis of the hollow insulating tube (4) in a ring shape at equal intervals.

4. A radio frequency source matcher characterized by: An RF source matching device comprising the hollow structure magnetic field driven vacuum variable capacitor of any one of claims 1-3. An RF source matching device comprising the hollow structure magnetic field driven vacuum variable capacitor of any one

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